v3.25.4
Investment Risks - Morgan Stanley Institutional Liquidity Funds - MSILF Treasury Securities Portfolio
Oct. 31, 2025
Prospectus [Line Items]  
Risk [Text Block] You could lose money by investing in the Fund.
Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency.
Credit and Interest Rate Risk [Member]  
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Credit and Interest Rate Risk. Credit risk refers to the possibility that the issuer or guarantor of a security, or counterparty to a transaction, will be unable or unwilling or perceived to be unable or unwilling to make interest payments and/or repay the principal on its debt or otherwise honor its obligations, including the risk of default. In such instances, the value of the Fund could decline and the Fund could lose money. If an issuer’s, guarantor’s or counterparty’s financial condition worsens, the credit quality of the issuer, guarantor or counterparty may deteriorate. Credit ratings may not be an accurate assessment of financial condition, liquidity or credit risk. Although credit ratings may not accurately reflect the true credit risk of an instrument, a change in the credit rating of an instrument or an issuer, guarantor or counterparty, or the market’s perception of the creditworthiness of an instrument or issuer, guarantor or counterparty can have a rapid, adverse effect on the instrument’s value and liquidity and make it more difficult for the Fund to sell at an advantageous price or time. Interest rate risk refers to the decline in the value of a fixed-income security resulting from changes in the general level of interest rates. A wide variety of market and economic factors can cause interest rates to rise or fall, including central bank monetary policy, rising inflation, disinflation or deflation, and changes in general economic conditions. When the general level of interest rates goes up, the prices of most fixed-income securities go down. When the general level of interest rates goes down, the prices of most fixed-income securities go up but the yield or income from new issuances of fixed-income securities generally decreases. Securities with longer durations will generally be more sensitive to changes in interest rates than securities with shorter durations. Fluctuations in interest rates may also affect the liquidity of and income generated by fixed-income instruments held by the Fund. The Fund may face a heightened level of interest rate risk in times of monetary policy change and/or uncertainty, such as when the Federal Reserve Board adjusts a quantitative easing program and/or changes rates. Changing interest rates may have unpredictable effects on the markets and may detract from Fund performance. A changing interest rate environment increases certain risks, including the potential for periods of market volatility and increased redemptions.
Fixed-Income Securities [Member]  
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Fixed-Income Securities. Fixed-income securities are subject to the risk of the issuer’s inability to meet principal and interest payments on its obligations (i.e., credit risk) and are subject to price volatility resulting from, among other things, interest rate sensitivity (i.e., interest rate risk), market perception of the creditworthiness of the issuer and general market liquidity (i.e., market risk). Securities with longer durations are likely to be more sensitive to changes in interest rates, generally making them more volatile than securities with shorter durations. The Fund may be subject to certain liquidity risks that may result from the lack of an active market and the reduced number and capacity of traditional market participants to make a market in fixed-income securities.
U.S. Treasury Obligations [Member]  
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U.S. Treasury Obligations. U.S. Treasury obligations, which are backed by the full faith and credit of the United States, have historically involved minimal risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund. Securities issued or guaranteed by the U.S. Treasury are backed by the full faith and credit of the United States but are guaranteed only as to the timely payment of interest and principal when held to maturity. In addition, notwithstanding that U.S. Treasury obligations are backed by the full faith and credit of the United States, circumstances could arise that could prevent the timely payment of interest or principal, such as reaching the legislative “debt ceiling.” Such non-payment could result in losses to and redemptions from the Fund.
U.S. Government Securities [Member]  
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U.S. Government Securities. The U.S. government securities in which the Fund invests can be subject to two types of risk: credit risk and interest rate risk. When the general level of interest rates goes up, the prices of most fixed-income securities go down. When the general level of interest rates goes down, the prices of most fixed-income securities go up. While the credit risk associated with these U.S. government securities generally is considered to be minimal, the interest rate risk can be substantial.
Market and Geopolitical Risk [Member]  
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Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic and other events that affect the  U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact the Fund’s ability to sell securities and/or its ability to meet redemptions. The risks associated with these developments may be magnified if certain social, political, economic and other conditions and events (such as war, natural disasters or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation,
interest rate changes and supply chain disruptions) adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value of the Fund’s investments, adversely affect the Fund’s ability to maintain a stable $1.00 share price and exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
Large Transactions Risk [Member]  
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Large Transactions Risk. The Fund may experience adverse effects when certain large shareholders, or a number of shareholders collectively, purchase or redeem large amounts of shares of the Fund, which may occur rapidly or unexpectedly. Such larger than normal shareholder redemptions may adversely affect the Fund’s ability to maintain a stable $1.00 share price and negatively impact the Fund’s liquidity. In some circumstances, the Fund may hold a relatively large proportion of its assets in cash in anticipation of large redemptions. These large redemptions may also force the Fund to sell portfolio securities or other assets when it might not otherwise do so, which may adversely affect the Fund’s ability to maintain a stable $1.00 share price and increase the Fund’s transaction costs. In addition, large purchases of Fund shares may adversely affect the Fund’s performance to the extent that the Fund is delayed in investing new cash and is required to maintain a larger cash position than it ordinarily would.
Stable NAV Risk [Member]  
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Stable NAV Risk. The Fund may not be able to maintain a stable $1.00 share price at all times. If the Fund or another money market fund fails to maintain a stable NAV (or if there is a perceived threat of the inability to maintain a stable NAV), the Fund could be subject to increased redemptions, which may adversely impact the Fund’s ability to maintain a stable $1.00 share price.
Active Management Risk [Member]  
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Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.